Conductive hearing loss – wikipedia fluid trapped in ear

Fluid accumulation is the most common cause of conductive hearing loss in the middle ear, especially in children. [2] Major causes are ear infections or conditions that block the eustachian tube, such as allergies or tumors. [2] Blocking of the eustachian tube leads to decreased pressure in the middle ear relative to the external ear, and this causes decreased motion of both the ossicles and the tympanic membrane. [3]

• Congenital malformation of the ossicles. This can be an isolated phenomenon or can occur as part of a syndrome where development of the 1st and 2nd branchial arches is seen such as in Goldenhar syndrome, Treacher Collins syndrome, branchio-oto-renal syndrome etc.

• Barotrauma unequal air pressures in the external and middle ear. [3] This can temporarily occur, for example, by the environmental pressure changes as when shifting altitude, or inside a train going into a tunnel.

It is managed by any of various methods of ear clearing manoeuvres to equalize the pressures, like swallowing, yawning, or the Valsalva manoeuvre. More severe barotrauma can lead to middle ear fluid or even permanent sensorineural hearing loss.

Conductive hearing loss makes all sounds seem faint or muffled. The hearing loss is worse in low frequencies. Congenital conductive hearing loss is usually identified through newborn hearing screening or may be identified because the baby has microtia or other facial abnormalities. Conductive hearing loss developing during childhood is usually due to otitis media with effusion and may present with speech and language delay or difficulty hearing. Later onset of conductive hearing loss may have an obvious cause such as an ear infection, trauma or upper respiratory tract infection or may have an insidious onset related to chronic middle ear disease, otosclerosis or a tumour of the naso-pharynx. Earwax is a very common cause of a conductive hearing loss which may present suddenly when water gets behind the wax and this blocks the ear canal. Diagnosis [ edit ]

For basic screening, a conductive hearing loss can be identified using the Rinne test with a 256 Hz tuning fork. The Rinne test, in which a patient is asked to say whether a vibrating tuning fork is heard more loudly adjacent to the ear canal (air conduction) or touching the bine behind the ear (bone conduction), is negative indicating that bone conduction is more effective that air conduction. A normal, or positive, result, is when air conduction is more effective than bone conduction. With a one-sided conductive component the combined use of both the Weber and Rinne tests is useful. If the Weber test is used, in which a vibrating tuning fork is touched to the midline of the forehead, the person will hear the sound more loudly in the affected ear because background noise does not mask the hearing on this side.

Pure tone audiometry, a standardized hearing test over a set of frequencies from 250Hz to 8000Hz, may be conducted by a medical doctor or audiologist or audiometrist, with the result plotted separately for each ear on an audiogram. The shape of the plot reveals the degree and nature of hearing loss, distinguishing conductive hearing loss from other kinds of hearing loss. CT scan [ edit ]

Most causes of conductive hearing loss can be identified by examination but if it is important to image the bones of the middle ear or inner ear then a CT scan is required. CT scan is useful in cases of congenital conductive hearing loss, chronic suppurative otitis media or cholesteatoma, ossicular damage or discontinuity, otosclerosis and third window dehiscence. Specific MRI scans can be used to identify cholesteatoma. Pathophysiology [ edit ]